Various printing methods are presently being known for printing of information. Ink jet printing methods are being widely used for printing apparatuses, copying machines, etc., because they enable printing apparatuses, etc., to be easily designed which operate with a reduced noise level and are reduced in manufacturing cost, in running cost, and in size.
Serial ink jet printing apparatuses have been arranged to perform printing so far in such a manner that main scanning with a printhead and sub scanning by transporting a printing medium are alternately repeated to perform printing of one page. In such printing apparatuses, the printhead has printing elements including ejection openings (nozzles) and ejection energy generating elements for ejecting ink selectively from the nozzles.
In recent years, there has been a tendency to increase both the number of printheads and the number of ejection openings of one printhead to enable multicolor printing, to improve the image quality and the resolution and to increase the printing speed.
Ordinarily, a printing apparatus of the above-described kind is provided with a multiplicity of registers for a hardware setting as to whether or not each ejection opening is used for printing. Correspondingly, the number of gates of a control logic circuit in the form of an application-specific integrated circuit (ASIC) or the like is increased.
The capacity corresponding to an image to be printed by using all the ejection openings is required as the capacity of a memory (random-access memory (RAM)) for storing image data, while part of the ejection openings of the printing read are not used in some printing mode. In printing in such a printing mode, it is necessary to control drive of the rejection openings used in a mask or ASIC setting or the like. In such a case, to control operation as software the capacity of a read-only memory (ROM) is increased with the increase in program storage capacity.
Further, a printing apparatus is arranged so that a selection can be made from various printing modes and user settings for multiple functions. Control operations according to such settings are mainly performed in the printing apparatus. Therefore the number of gates of the logic circuit and the capacity of the ROM for such control operations tend to increase.
Thus, if control becomes complicated with the improvement in quality of printed images and the increase in the number of functions, the number of gates of the logic circuit and the capacity of the ROM are increased and an increase in manufacturing cost of the entire apparatus results.